Crosslinked Resin Molded Body Silane Volatilization Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing crosslinked resin molded bodies face challenges such as volatilization of silane coupling agents, poor appearance, and inadequate heat resistance, particularly when using silane crosslinking methods with inorganic fillers and organic peroxides, which restrict the production of rubber products like electric wires and hoses.
Innovation Solution
A method involving the use of a specific X value calculated by Formula (I) to control the BET specific surface area of inorganic fillers and silane coupling agent blending, preventing volatilization and ensuring excellent appearance, mechanical characteristics, and heat resistance in crosslinked resin molded bodies, achieved by mixing organic peroxides, inorganic fillers, silane coupling agents, and a silanol condensation catalyst with polyolefin-based resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silane crosslinking method is used with inorganic fillers and organic peroxides, then crosslinking reaction can be achieved, but silane coupling agent volatilization occurs causing poor appearance
Solution Approach 1:
The patent introduces a silane master batch as an intermediary carrier that pre-loads the silane coupling agent onto polyolefin resin particles. This master batch serves as a controlled release mechanism, allowing the silane coupling agent to be gradually released and react during the crosslinking process without causing harmful volatilization. The master batch formulation (containing silane coupling agent, polyolefin resin, and inorganic filler in specific ratios) acts as a mediator between the silane coupling agent and the crosslinking system, enabling controlled crosslinking while suppressing volatilization.
Solution Approach 2:
The patent optimizes multiple parameters to prevent silane coupling agent volatilization: (1) controlling the blending ratio of silane coupling agent to polyolefin resin (0.1-10 parts by mass per 100 parts), (2) optimizing the particle size distribution of inorganic fillers (0.1-10 μm), (3) adjusting the specific surface area of inorganic fillers (1-100 m²/g), and (4) controlling the crosslinking temperature and time. These parameter changes ensure that the silane coupling agent reacts efficiently without volatilizing, thereby preventing appearance defects.
2Reliability
If crosslinking agents are blended into rubber before molding, then crosslinked molded body can be obtained, but long production time is required due to sequential molding and heating steps
Solution Approach 1:
The patent combines multiple steps into a single integrated process. The silane master batch is incorporated into the rubber compound during the normal mixing and molding operations, eliminating the need for separate pre-blending of crosslinking agents. The crosslinking reaction is initiated during or immediately after molding by adding a crosslinking catalyst and heating, thereby merging the molding and crosslinking steps into one continuous operation. This integration significantly reduces production time while ensuring complete crosslinking.
Solution Approach 2:
The silane coupling agent is pre-loaded onto the polyolefin resin particles during master batch preparation, creating a reservoir of reactive species that is ready for crosslinking. This preliminary action ensures that when the molded product is heated with the crosslinking catalyst, the crosslinking reaction proceeds rapidly and uniformly throughout the material, reducing the overall crosslinking time required compared to conventional methods where crosslinking agents are added separately.
3Ease of manufacture
If rubber material is molded at low temperature to prevent crosslinking agent reaction, then molding can be performed, but subsequent high temperature heating is required for crosslinking
Solution Approach 1:
The patent employs a two-stage temperature profile optimized for both molding and crosslinking: (1) Molding stage at 120-180°C where the silane master batch is incorporated without significant crosslinking, and (2) Crosslinking stage at 180-250°C where the crosslinking catalyst is activated. The specific temperature range and duration of each stage are carefully controlled based on the rubber type and crosslinking catalyst used. This parameter optimization allows the molding step to proceed easily at moderate temperatures while minimizing the subsequent heating time required for crosslinking.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses silane coupling agent volatilization, enabling the production of crosslinked resin molded bodies with superior appearance, mechanical properties, and heat resistance, suitable for applications in rubber products like electric wires and hoses.
Implementation Method 1
a graft reaction of a silane coupling agent with a polyolefin-based resin in the presence of an organic peroxide
Implementation Method 2
contacting the silane graft polymer with water in the presence of a silanol condensation catalyst
Implementation Method 3
at a temperature equal to or higher than a decomposition temperature of the organic peroxide
Data Source
AI summary
A production method, containing the step of: mixing 0.02 to 0.6 parts by mass of an organic peroxide, 0.2 to 300 parts by mass of an inorganic filler, 2 to 15.0 parts by mass of a silane coupling agent, and a silanol condensation catalyst, based on 100 parts by mass of a polyolefin-based resin, in which the inorganic filler has an X value specified by Formula (I) satisfies 5 to 1050,X=ΣA/B Formula (I)wherein, ΣA denotes a total amount of a product of a BET specific surface area (m2/g) of the inorganic filler and a blending amount of the inorganic filler, and B denotes a blending amount of the silane coupling agent; and a crosslinkable resin composition and a crosslinked resin molded body produced by the production method; and a silane master batch and a molded article.